ML20059M854
| ML20059M854 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 08/18/1993 |
| From: | AFFILIATION NOT ASSIGNED |
| To: | |
| References | |
| OLA-2-I-MFP-033, OLA-2-I-MFP-33, NUDOCS 9311190383 | |
| Download: ML20059M854 (17) | |
Text
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c s-U~ 76 3 2 Od - L NCR-DCl 21'Rev. O July 8, 1993 93 tr 28 0 6 :28 NCR DC1-93-TP-N021 INADEQUATE STP I-33A JULY 8, 1993 MANAGEMENT
SUMMARY
On November 7, 1992, with Unit 1 :in Mode 3' (Hot Standby), during.
startup following the fifth refueling outage, the requirements of Technical Specifa. cation (TS) 3.3.2 Action 18 for the Unit 1 containment ventilation isolation (CVI) function were not met when the containment purge valves were opened with the CVI function inoperable.
The purge valves were opened similarly on.
January 27, 1993,-February 7,-1993, and March 26, 1993.
These four events were preceded by implementation of a Unit 1 design change replacing the radiation monitors used for CVI initiation.
On October 18, 1993, the CVI function was declared operable.
This declaration was based on a surveillance test that was inadequate due to incomplete response time testing.
The inadequacy of the surveillance test was not discovered untill April 20, 1993, following the same design change on Unit 2.
The surveillance test for the CVI function was reperformed and successfully completed on April 22, 1993', and the CVI. function was declared operable on April 23, 1993.
The root cause of this event was lack'of clear identification of CVI time response testing requirements (for Modes 1-4) in STP I-33A.
To prevent recurrence of this event, the surveillance test procedures will be revised to more clearly state the requirements for response time testing of the'CVI function.
aum waan.
som.
This event was reported to the NRC on May 20, 1993, via LER 1 031-00.
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93NCRWP\\93TPN021.KAB/sdl Page 1
of 17 9311190383 930018 E PDR ADOCK 05000275.
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s NCR DC1-93-TP-N021 Rev. 0 July 8, 1993 NCR DC1-93-TP-N021 l
INADEQUATE STP I-33A I.
Plant Conditions Unit 1 was in Mode 1 (Power Operation) at 100% power.
II.
Description of Event A.
Summary:
On November 7, 1992, the requirements of Technical Specification (TS) 3.3.2 Action 18 for the Unit 1 containment ventilation isolation (CVI) function were not met when the containment purge valves were opened with the CVI function inoperable.
The purge valves were similarly opened on January 27, 1993, February 7, l
1993, und March 26, 1993.
B.
Background:
TS 3.3.2, Table 3.3-3, Line 3.c.1 requires two channels of CVI automatic actuation logic and actuation relays to be operable in Modes 1 (Power Operation), 2 (Startup), 3 (Hot Standby), and 4 (Hot Shutdown).
Action 18 of this TS allows plant operation with less than two channels operable, provided the containment purge supply and exhaust valves (RCV-11, 12, FCV-660, 661, 662, 663, and 664) are maintained closed.
TS 4.3.2.2 requires that the response time of each Engineered Safety Feature Actuation System (ESFASj function (including"the CVI function'i be demonstrated "
to be within the limits of Table 3.3-5 " Engineered Safety Features Response Times," at least once per 18 months.
Each test shall include one SSPS train such that both trains are tested at least once per 36 months, and at least one channel per ESFAS func' tion (ref. 1).
STP I-33A, " Reactor Trip and ESF Response Time Test,"
evaluates the overall response times of various ESFAS features, including CVI, to fulfill TS 4.3.2.2.
STPs I-39-R44A.C and I-39-R44B.C " Containment Ventilation Exhaust Rad Monitor RM-44A(B) Time Response Test,"
collect the CVI response time data which are then input i
to STP I-3'A for evaluation.
93NCRWP\\93TPN021.KAB/sdl Page 2
of 17
NCR DC1-93-TP-N021 Rev. O
~ July'8, 1993-Response time testing may be excluded foricomponents if!
their response times are verified.by other functional testing.
In order to justify exclusion', it must be.
demonstrable that changes in response time beyond-acceptable limits are accompanied by changes in.
performance characteristics that are detectable during-routine functional testing.
All. electro-magnetic relays have' finite' response' times.
associated with the timeirequired for the relayLcoil to-energize and actuate the moveable contacts.
This-time i
is dependent on the period required.for,the magnetizing or inrush currents to' reach steady. state.
The response time for the. relay may be taken from-the-testing of a representative contact'which changes state-on relay actuation.
The response time for each. individual cortact is not required since the1 functionality of each=
contact is verified during routine-functional testing.
The impact of response time testing is minimized by-ensuring all components with finite response times are:
tested, without-duplicating testing paths 1(ref. 5).
Valves FCV-678, 679, and 681 would also~close on afCVI signal, although they are not required by:TS 3.'3.2-Action 18~to be closed when CVI is' inoperable.
Closing valves FCV-678, 679, and'681 renderc the Containment Atmosphere Particulate Radioactivity Monitoring System j
inoperable and enters TS 3.4.6.1.(ref. 1)L.
i TS 3.4.6.1 allows plant operation to' continue for upito.
.l 30 days if one of the following'systemslis' inoperable.
(a) Containment'Atmospherc articulate Radioactivity M6nitoring System, (b) Containment Structure Sumps'and i
l Reactor Cavity Sump Level and Flow'MonitoringESystem, or (c) Either the Containment Fan, Cooler Collection Monitoring System or the Containment Atmosphere Gaseous Radioactivity Monitoring System (ref. 1).
STP V-663 is used to perform leak testing following:
i opening and closure of valves FCV-662,.663, or 664 (for containment purges) in Modes 1 through 4.
C.
Event
Description:
On August 21, 1992, Design Change Package ' (DCP)
J-47031, Revision 0, was issued to replace plant vent radiation monitors RM-11, RM-28A and B, RM-12,-and l
RM-14A and B, which provide a CVI function with RM-44A1 93NCRWP\\93TPN021.KAB/sdl Page 3
of' 17 I
a
-m-,
9 l
i NCR DCl-93-TP-N021 Rev. 0 July 8, 1993 l
and RM-44B.
In conjunction with the DCP, STPs l
I-39-R44A.C and I-39-R44B.C were being written to test the response times of the new radiation monitors.
The high radiation output relay on each of the two new radiation monitors was connected directly to each of l
the two trains of the SSPS via separate contacts on the same relay.
Since no devices were added between the radiation monitors and the SSPS inputs, only two response time tests, one for each train,_would be veguired to fully test all components with finite response times in the CVI path (see Figure 1).
During reviews of Revision 0 of the DCP, Design Engineering recognized that a failure in either RM-44A or RM-44B could potentially affect both SSPS trains, A and B.
The directly-connected output relays could not be qualified for contact-to-contact separation due to the close proximity of the contacts.
Design Engineering revised the DCP to add two relays to isolate the two SSPS trains from each other for a-postulated failure of one of the radiation monitors.
Revision 1 of DCP J-47031 was initiated to include two isolation relays with. qualified contact separation.
During discussions with Design Engineering, this change was noted by the writers of STPs I-39-44A.C-and I-39-44B.C.
As in Revision 0 of the design, two response time tests were adequate to fully test all components with finite response times in the CVI actuation paths.
Design Engineering determined-thEt the desired type of isolation relay could not be obtained.
Consequently, Revision 1 of tun +"CP was' issued requiring a differentE
=.
type of relay.
The change in the type of relay required a change in configuration, resulting in a total of four new relays to achieve adequate separation (one from each radiation monitor to each train of SSPS).
This configuration required additional response time testing, increasing the number of paths for response time tested from two to four.
On September 14, 1992, Revision 1 to DCP J-47031 was approved.
When Revision 1 was issued, the change in the number of relays was recognized by the procedure writers.
However, they did not recognize that this had an effect on the response time testing.
i 93NCRWP\\93TPN021.KAB/sdl Page 4
of 17 i
NCR DC1-93-TP-N021 Rev. O July 8, 1993 On October 14, 1992, STPs I-39-R44A.C and I-39-R44B.C i
were performed on two of the Tour response paths to demonstrate CVI operability prior to returning CVI to service, and to meet post-modification testing l
requirements associated with implementing the design change.
On October 18, 1992, the CVI function was declared operable, based on the completion of the DCP acceptance.
tests, including I-39-R44A.C and I-39-R44B.C.
On November 3, 1992, based on the review of STP I-33A, l
all of the reactor trip and ESF response time channels l
required for Mode 4 entry were declared operable.
This included the CVI channels from high radiation through j
l SSPS, on the basis of the deficient data obtained from l
STPs I-39-R44A.C and I-39-R44B.C.
On November 4, 1992, Unit 1 entered Mode 4.
This_ mode transition and subsequent transitions to Modes 3, 2,
and 1, met the requirements of TS 3.0.4 since TS 3.3.2, l
Table 3.3-3, Action 18 does not require a plant shutdown.
On November 7, 1992, the requirements of TS 3.3.2 Action 18 for the Unit 1 CVI function were not met when the containment purge valves were opened with the CVI function inoperable.
The purge valves were aimilarly opened on January 27, 1993, February 7, 1993,_and' March 26, 1993.
On April 20, 1993, during preparations for STP I-33A on Unit 2, System
- Engineering identified the. deficiencies with the November 3, 1992, STP I-33A for-the CVI function (i.e., STPs I-39-R44A.C and I-39-R44B.C did not fully take into account the potential time delays introduced by the new output isolation relays installed as part of the radiation monitor design change).
On April 20, 1993, the Unit 1 Shift Foreman declared the CVI function inoperable and entered TS 3.3.2 Action 18.
The containment purge. valves were verified to be closed, and were administrative 1y tagged out to maintain them closed until the response time testing could be reperformed.
93NCRWP\\93TPN021.KAB/sdl Page 5
of 17
NCR DC1-93-TP-N021 Rev. O July 8, 1993 On April 23, 1993, the response time testing was successfully performed with revised STPs I-39-R44A.C and I-39-R44B.C, and TS 3.3.2 was exited.
D.
Inoperable Structures, Components, or. Systems that Contributed to the Event:
None.
E.
Dates and Approximate Times for Major Occurrences:
1.
November 7, 1992:
Event date.
TS 3.3.2 Action 18 was exceeded when Unit 1 containment purge valves were opened while CVI was inoperable due to incomplete response time testing.
Subsequent containment discharges occurred on January 28, 1993, February 3,
- 1993, February 8, 1993, and March 26, 1993.
l 2.
April 20, 1993:
Discovery date.
System Engineering identified deficiencies with the November i
7, 1992 STP I-33A (ref. 2).
F.
Other Systems or Secondary Functions Affected:
Containment purge valves RCV-11,_12, FCV 660, 661, 662, 663, 664 are listed in TS 3.3.2 Action 18 as required-to'be closed if lessthan 2 channels ~8f CVI are
~~
Containment atmosphere particulate monitoring valves FCV-678, 679, and 681 are not-specifically called out as required to be closed by TS 3.3.2 Action 18, but would automatically close on a CVI signal.
G.
Method of Discovery:
On April 20, 1993, System Engineering identified the deficiencies in the November 7, 1992 performance of STP I-33A on Unit 1 during preparations for STP I-33A on Unit 2.
93NCRWP\\93TPN021.KAB/sdl Page 6
of 17
i l
i '. -
l NCR DC1-93-TP-N021 Rev.
O' July 8, 1993 H.
Operator Actions:
l On April 20, 1993, the Shift Foreman declared the CVI-function inoperable and entered TS 3.3.2_ Action 18.
The containment purge valves were verified to be closed, and were administratively tagged out to maintain them closed until the response. time testing could be reperformed (ref. 2).
I.
Safety System Responses:
None.
III. Cause of the Event A.
Immediate Cause:
The immediate cause of the CVI TS being exceeded was the incomplete response time testing of the CVI function.
B.
Determination of Cause:
l See
Attachment:
Root Cause Analysis C.
Root Cause:
The root cause of this event was lack of clear identification of CVI time response testing requirements (for Modes 1-4) in STP I-33A.
IV.
Analysis of the Event A.
Safety Analysis:
Following the design change that installed the radiation monitors and output isolation relays, each of i
the radiation monitors was functionally tested and verified to actuate each train of the SSPS with a CVI signal.
Furthermore, response time testing performed after the discovery of the event verified that the CVI l
function met the required response times for all combinations of RM-44A, RM-44B, and the'two trains of i
SSPS.
Therefore, the CVI would have functioned properly if called upon.
Consequently, this event did not adversely affect the health and safety of the public.
93NCRWP\\93TPN021.KAB/sdl Page 7
of 17
~
NCR DCl-93-TP-N021 Rev. O July 8, 1993 B.
Reportability:
1.
Reviewed under QAP-15.B and determined to be non-conforming in accordance_with Section 2.1.2 as a non-routine event _that may require reporting to the NRC.
2.
Reviewed under 10 CFR 50.72 and 10 CFR 50.73 per i
NUREG 1622 and determined to be reportable in accordance with 10 CFR SC.73 (a) (2) (1) (B) as a condition exceeding the plant TS.
The report associated with this NCR is LER 1-92-031-00.
3.
Reviewed under 10 CFR Part 21 and determined that this event or condition will not require a 10 CFR 21 report, since it is being reported under'10 CFR 50.73, and it does not involve defects.iu vendor-supplied services / spare parts'in stock.
4.
This event or condition will not be reported via an INPO Nuclear Network entry.
5.
Reviewed under 10 CFk 50.9 and determined to be not reporthble since this event does not have a-significant implication for public health and safety or common defents and security.
1 6.
Reviewed under the criteria of AP C-29 requiring the issue and approval of an OE and determined that an OE is not required.
V.
Corrective Actions
<c..
A.
Immediate Corrective Actions:
l 1.
The containment purge valves were verified to be i
i closed, and were administratively tagged out to maintain them closed until response time testing could be reperformed (ref. 2).
2.
The surveillance test procedures. were revised and complete response time tcating was performed satisfactorily.
B.
Investigative Actions:
1.
Evaluate the performance of CVI time response testing via the Mode 6 bypass for acceptability in 93NCRWP\\93TPN021.KAB/sdl Page 8
of 17 t
y w
r
NCR DC1-93-TP-N021 Rev. O July 8, 1993 Modes 1 through 4.
Include the results of NPRDS search of relay reliability.
RESPONSIBILITY:
V. Backman.
ECD:
05/04/93 STATUS:
Return DEPARTMENT:
System Engineering Tracking AR:
A0304344, AE #01.
1.
Prepare and submit to the NRC a Licensee Event Report (LER) in accordance with 10 CFR 50.73 for a condition exceeding the Tech. Specs.
l RESPONSIBILITY:
Sisk/Natividad/Bruno ECD:
05/20/93 STATUS:
Complete l
DEPARTMENT:
Regulatory Compliance l
Tracking AR:
A0304344, AS #02 3.
Investigate other sources of time response data-that could validate the CVI' cross-train response times.
RESPONSIBILITY:
Nowlen/ Reed ECD:
'05/04/93 STATUS:
Assigned DEPARTMENT:
I&C Tracking AR:
A0304344, AE #03 4.
Evaluate these other sources of time re=ponse data (from Investigative Action #3 above, AE #03) to determine whether the CVI met its response time requirements.
RESPONSi$[LITY:
V.
Backman ECD:
0$/$~4/93
~
~"
STATUS:
Return DEPARTMENT:
System Engineering Tracking AR:
A0304344, AE #04 5.
Evaluate the procedures listed in-STP I-33A Table 4 for those procedures that should contain a note stating that test results will be used for STP I-33A.
RESPONSIBLE:
V.
Backman ECD: 07/01/93 l
STATUS:
Returned l
DEPARTMENT:
System Engineering i
Tracking AR:
A0304344, AE #08 93NCRWP\\93TPN021.KAB/sdl Page 9
of 17 l
l
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NCR DC1-93-TP-N021 Rev. O U
July 8, 1993 C.
Corrective Actions to Prevent Recurrence:
1.
Revise STP I-33A to clearly state the response time testing requirements of the Reactor Trip and FSF functions.
RESPONSIBLE:
V.
Backman DEPARTMENT:
System Engineering Tracking AR:
A0304344, AE #06-Outage Related?
No OE Related?
No t
NRC Commitment?
Yes CMD Commitment?
Yes STATUS:
Assigned ECD:
12/31/93 2.
Issue a lessons learned ma.no describing this event to ;.1 DCN sponsors.
RESPONSIBLE:
D.
Shelley DEPARTMENT:
Nuclear Engineering i
Tracking AR:
A0304344, IG #07 Outage Related?
No
{
OE Related?
No NRC Commitment?
Yes l
CND Commitment?
No STATUS:
Assigned ECD:
7/1/93 l
3.
Revise the I&C procedures 3 4 ated on AE #08 of this AR with the following changes:
Add a statement to each procedure's a.
Discussion.section similar to-what follows:
The time response portion of this test is performed to obtain data for STP I-33A,
" Reactor Trip and ESF Response Time Test."
Time response is required to be performed whenever the transmitter is replaced to obtain baseline data.
Refer to STP.I-33A for overall scheduling and guidance.
b.
Add STP I-33A to each procedure's Reference section.
c.
Add a line at the end of the data sheet to forward a copy of the data section to the SSPS System Engineer for inclusion in I-33A.
93NCRWP\\93TPN021.KAB/sdl Page 10 of 17
1 d
t NCR DC1-93-TP-N021 Rev. O July 8, 1993 RESPONSIBLE:
M. Brewer DEPARTMENT:
I&C Tracking AR:
A0304344, AE #09 Outage Related?
No i
OE Related?
No NRC Commitment?
Yes CMD Commitment?
Yes STATUS:
Assigned ECD:
12/31/93 4.
Make appropriate changes to FSAR Chapter 6, DCM S-39, and DCM-16 revisions to reflect.and clarify.
the Mode 1-4 time-response. requirements for the CVI function.
RESPONSIBLE: Tien Lee DEPARTMENT: NCEN Tracking AR:
A0304344, AE #10 Outage Related?
No OE Related?
No NRC Commitment?
No CMD Commitment?
No STATUS:
Assigned ECD:
12/31/93 D.
Prudent Actions (not required for NCR closure)
Not required.
VI.
Additional Information A.
Failed Components:
None-
~
B.
Previous Similar Events:
NCR DC1-92-OP-N059/LER 1-92-027-00:
This prev
's NCR/LER reported a violation of CVI TS 3.3.2 Acm sn.18 during the containment discharge on November 7, 1992.
However, that event was due to a personnel error in the incorrect positioning of a damper to bypass the'CVI radiation monitors.
Because the current event occurred during the same time period but.was not related to improper system or damper alignments, the corrective actions from the previous NCR/LER'did not prevent the current event.
93NCRWP\\91TPN021.KAB/sdl Page 11 of 17
NCR DC1-93-TP-N021 Rev. O July 8, 1993 C.
Operating Experience Review:
1.
NPRDS:
j Not applicable.
2.
NRC Information Notices, Bulletins, Generic Letters:
None.
3.
None.
D.
Trend Code:
Responsible department: TP (Plant Engineering);
cause code: B3 (Procedural Deficiency, Procedure Incomplete).
E.
Corrective Action Tracking:
1.
The tracking action request is A0304344.
2.
Are the corrective actions outage related?
No.
F.
Footnotes and Special Comments:
None.
G.
References:
~
1.
Technical Specifications 3.3.2 and 4.3.2.2 Technical Specification 3.4.6.1 Technical Specification 3.0.4 and 4.0.4 2.
Initiating Action Request A0304150 3.
DCP J-047031 Rev. O DCP J-047031 Rev. 1 Implementing Work Order C0105272
(" Perform Time Response Test")
4.
Surveillance Test Procedure I-33A Surveillance Test Procedure I-39-R44A.C Surveillance Test Procedure I-39-R44B.C 93NCRWP\\93TPN021.KAB/sdl Page 12 of 17
NCR DC1-93-TP-N021 Rev. O July 8, 1993 5.
Response to Investigative Action #1 (A0304344, AE
- 01) from System Engineering (V. Backman) 6.
AR A0274357, Implement DCP J-47031: RE-44 A/B CVI changeover.
7.
AR A0256476, Implement DCP.J-47031: RE-44A/B CVI changeover.
o.
Shift Foreman & Control Logs dated: October 14-18, 1992.
9.
Schematic of RM-44 A/B to SSPS trains A/B.
10.
Containment Purge Records & Control Room Logs dated: 11/6/92, 1/27/92, and 2/7/93.
H.
TRG Meeting Minutes:
On April 26, 1993, the initial TRG convened and considered the following:
1.
The TRG reviewed the system configuration and the details of the problem.
There are two basic l
issues:
(1).due to the addition of the isolation l
relays, time response testing now needs to include each of the four new relays; and (2) the 1R5 test was done with the Mode 6 bypass switched
- 4. n.
A third issue that came up was why STP I-33A has not been testing both channels'for both trains in the past.
2.
Investigative actions were" assigned to evalhate-
'"~
,c whether we have enough data from other' sources to be able to say that the CVI-function would have l
passed the STP.
If not, this event will be reportable as a 30-day Licensee Event Report to the NRC.
Some of this data is already being looked at.
i 3.
There wac some misunderstanding among the HIT team when the Rev. 1 DCN came in -~I&C reviewed the DCN-for PMT concerns, but thought that the relays were only being added to the cross-train wiring and l
that existing tests would cover the' final configuration.
In addition, there were a lot of other field changes in.the short time while the l
DCN was implemented.
l 93NCRWP\\93TPN021.KAB/sdl Page 13 of 17 i
1 l
~
NCR DC1-93-TP-N021 Rev. O July 8, 1993-4.
Initial thoughts towards root cause analysis brought up several points:
the time response requirements for CVI are somewhat obscure, not too many people are familiar with them, the I&C procedure writer did not know all the facts about the DCN, and there were cross-discipline reviews by Ops and Chemistry, but not by System Engineering.
System Engineering may or may not have caught it at that time; although they were the ones that finally caught it.
STPs I-39-R44A/B possibly differ from other STPs (like I-33B) by:
not testing both channels of each train.
5.
This TRG will reconvene on Tuesday, 5/4/93, to report on results of investigative actions.
On May 4, 1993, the TRG reconvened and considered the following:
1.
Although the relays were thoroughly. functionally tested, only the same-train response was timed.
TRG has not yet been'able to obtain data from other sources (e.g.,
main annunciator system) that would show that the CVI cross-trains also met their response time requirements during the IRS tests.
Investigations will continue; however, unless the data is found soon we will submit the LER for a condition prohibited by Tech Specs.
2.
The event date will be the point where we did not comply with the TS action statement after 1R5, because the STP near the end of 1R5 was
" essentially used7ike a PMT (everflhough the work ^^
orders were listed with no required PMT.
3.
The other issue of components not response time tested due to the Mode 6 bypass has been evaluated as acceptable (ref. 5).
4.
The TRG continued discussions on the event, some possible causal factors, and some possible corrective actions.
I&C will perform a preliminary root cause analysis; Regulatory Compliance will factor this into the LER to be drafted.
5.
The TRG will reconvene on Tuesday, 5/11/93, to discuss root cause and review the LER draft.
93NCRWP\\93TPN021.KAB/sdl Page 14 of 17
O 1
- o NCR DC1-93-TP-N021 Rev. O July 8, 1993 i
On May 11, 1993, the TRG reconvened and considered the following:
1.
The TRG reviewed and clarified the event description.
2.
The root cause was determined to be inadequate procedure in that STP I-33A did not include sufficient description of the requirements for response time testing.
It was noted that there is no comprehensive collection of response time testing information at DCPP, and that Tech Spec and FSAR requirements do not agree.
A contributory cause is the lack of a cross-disciplinary review of the procedures by System Engineering.
3.
The TRG assigned an investigative action to evaluate which procedures should contain a note stating that results will be used for STP I-33A.
(The corrective action to revise these procedures will be assigned later.)
Two corrective actions were assigned to (1) revise STP I-33A to clearly state the response time testing requirements of the CVI function and (2) to issuo a lessons learned memo to DCN sponsors.
In addition, the TRG discussed (but did not assign) actions to submit an FSAR revision request and to submit comments for a revision to DCM S-39.
4.
~~"The TRG will reconvene on Friday, 5/14/93, to
"~
review the LER draft.
On May 14, 1993, the TRG reconvened to review the LER.
Corrective actions 3 and 4 above were assigned.
On May 28, 1993, the TRG reconvened to review the root cause and the LER submitted on May 20, 1993.
The LER was determined to be satisfactory.
A correction was made to corrective action to prevent recurrence number 4 to specify that chapter 6 of the FSAR, DCM S-39, and DCM T-16 will be revised to reflect and clarify the Mode 1-4 time response requirements for j
the CVI function.
93NCRWP\\93TPN021.KAB/sdl Page 15 of 17 1
NCR DC1-93-TP-N021 Rev. O July 8, 1993 On June 24, 1993 the TRG reconvened.
The TRG reviewed and finalized the NCR write-up.
The TRG discussed the root cause and approved the following words:
The root cause of this event was requirements for CVI (in modes 1-4) time response test not clearly identified in STP I-33A.
The TRG discussed the trend code and agreed that the rceponsible department is Plant Engineering (TP) and the cause code is THE OVERALL ECD FOR THIS NCR IS FEBRUARY 11, 1994.
I.
Remarks:
- None, J.
Attachment:
Root Cause Analysis se 93NCRWP\\93TPN021.KAB/sdl Page 16 of 17
. ~.
. s' it p.
Attachment ROOT CAUSE ANALYSIS FOR NCR DC1-93-TP-N021 Effect
-Cause-l Technical Specification 3.3.'2,
- The response time Action 18, was exceeded when.
test, STP.I.-33A, was the containment purge. valves
-inadequate, were openarl without complete testing of CVI response time.
The response time test, STP' The radiation monitor [
I-33A. was inadequate.
DCP.was. revised but.
r
. the effect:of the~ design change on response time-was not recognized.
The radiation monitor DCP was
- The..mechanicsJof' response' i
design change on response time
. time testing /were-not revised but the effect of the clear'and.there.wasno1 was not recognized.
cross-disciplinary review-by System Engineering.
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' l The mechanics of-response time Root Cause:. The: require-testing were not-clear and ments for CVI Icoponse there was.no cross-disciplinary time testing: (for; Modes review by System Engineering.
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